1. Field of the Invention
The present invention relates to multifunctional urgent shutoff safety valves for preventing accidents such as explosion, fire, etc. due to the leakage of gas by closing the path of flow through sensitive reaction even when the fluid pressure at the outlet port side is lowered rapidly by excessive flow of the fluid due to an earthquake of stronger than a fixed level detected and indicated by the Richter seismometer or blowing-up of the pipe at the rear end of the outlet port side of the valve, or when the fluid pressure is increased rapidly due to abnormality including the fault of a pressure controller such as a governor for maintaining a constant fluid pressure of the pipe at the front end of the valve, etc.
No-power in the present invention refers to no need to have an electrical energy. Electronic parts such as an electronic sensor, electronic valve, etc. are completely excluded from being used in detecting an earthquake or a fluid pressure. Exclusion of any form of the electrical energy in the present invention is to be prepared for that the valve does not work at all when there occurs an accident of power failure due to an earthquake, etc.
2. Description of the Prior Art
In countries where there occur earthquakes frequently, basically, general construction objects including power supply lines, gas supply pipes, water pipes, buildings, etc. are constructed according to the earthquake-proof design. However, if a strong earthquake having a high seismic intensity occurs, it is not possible to prevent destruction of basic facilities fundamentally.
In order to minimize damages incurred due to natural disasters such as an earthquake, etc. or safety accidents such as blowing-up of gas pipes by the underground digging work, etc., i.e., the secondary damages such as the leakage of a large amount of gas, etc., pressure sensing devices or earthquake sensing devices are used. Almost all of such devices use detection sensors using the electrical energy. However, such devices have a very complicated structure as they include the configuration of the electrical circuit board or mechanical equipment, and are disadvantageous in that the rate of failure is very high, it is not possible to perform their functions during power failure, and their manufacturing cost is high. Particularly, in many cases of earthquakes having a high seismic intensity, accidents of power failure are accompanied. Therefore, it is not desirable to use valves using the electrical energy.
Conventionally, there have been known earthquake detection devices having many configurations to shut off the flow of fluid such as a gas, etc. by detecting an earthquake which is stronger than a fixed level. One of them is U.S. Pat. No. 5,307,699 (Seismic Initiator for Earthquake Shutoff Valves and the Like), of which configuration and operation are described below:
In the configuration of the above U.S. Pat. No. 5,307,699, a collar having a tapered inclination resting on a cavity is formed at the bottom of the center of the base of a housing at which the armature is installed, and a support is fixed to the center of a ferromagnetic pin. The mass is inserted in the upper portion of the pin so that the clearance is provided with between the pin and mass.
In the lower portion of the base of the above housing, a permanent magnet is inserted in such a way that the arm which is connected to a reset shaft is positioned directly below the cavity on which the above collar rests to allow pivoting. To the lower portion of the above arm, a valve seat is attached and fixed to open and close the gas outlet formed on the valve body.
The operational effects of U.S. Pat. No. 5,307,699 having the above configuration are reviewed as follows:
The above-described ferromagnetic pin maintains the vertical state by the magnetic force of a permanent magnet inserted into the above valve seat, which is open if the above arm is attached to the bottom of the housing. The arm of the valve seat is detached as the mass, and subsequently the ferromagnetic pin and collar, are shaken by the earthquake accelerations. And the detached arm closes the gas outlet ports on a diagonal line as it is pivoted along the reset shaft.
However, the U.S. patent having the above-described configuration and operational effects have many problems in that it is not possible to control the seismic intensity using the mass since the setting state of the mass into which the ferromagnetic pin is inserted is fixed at a constant position always; there may be a problem with maintaining the vertical state of the ferromagnetic pin as the clearance is formed between the ferromagnetic pin and mass and the weight of mass may be unbalanced; and the arm may not move smoothly if the space between the arm and reset shaft is corroded or is filled with foreign materials since the arm to which the valve seat is attached is pivoted as it is attached to the shaft.
It is therefore an object of the present invention to solve the above-described problems with conventional inventions and to provide with safety valves without using the electrical energy at all. In such safety valves, the outlet ports of the fluid such as gas, etc. are open when the spool assembly mounted on the valve body is suspended; the outlet ports are closed as the spool assembly suspended by the magnetic force is dropped down on the valve seat when the vibration of stronger than a fixed seismic intensity is delivered to the mass during an earthquake; there may incur the part processing tolerance and assembly tolerance from the separation distance between the permanent magnet and mass as well as allowable errors in the magnetic force of the permanent magnet while the magnetic force of the permanent magnet and the weight and separation distance of the spool assembly assume very important roles for the flow rate passing through the valve and the seismic intensity reaction sensitivity of an earthquake.
Accordingly, the technical problems to be solved in the present invention include making it possible to control movement of the mass by forming the screw unit for each step and mass to enable arbitrary control and setting of the separation distance from the mass and the permanent magnet; fine control and setting of the magnetic force by which the entire spool assembly is lifted up by having the mass base equipped with in the valve housing; and lowering significantly the rate of generation of working errors by extending the range of allowable errors in the magnetic force of the magnet and the range of processing allowable errors and assembly errors for the parts used for the valve of the present invention.